Fiber reinforced thermoplastic resin structure, process for production of same, and extruder for production of same

Abstract

A fiber reinforced thermoplastic resin structure comprising a thermoplastic resin and reinforcing fibers, having a ratio (Lw/Ln) of the number average fiber length (Ln) to the weight average fiber length (Lw) of the uniformly dispersed reinforcing fibers of 1.1 to 5, and having a weight average fiber length of 1.0 mm to 200 mm as well as a process and extruder for the production thereof.

What is claimed is:  
     
       1. A process for production of a fiber reinforced thermoplastic resin structure by melt extrusion by an extruder of a thermoplastic resin and a continuous roving, said process for production of a fiber reinforced thermoplastic rein structure comprising passing a molten thermoplastic resin and reinforcing fibers as a continuous roving through a control mechanism formed by processing a screw and/or cylinder to give at least part of the screw surface and/or the cylinder inner wall irregular surfaces and thereby controlling the degree of combing and/or fiber length of the reinforcing fibers in the thermoplastic resin matrix of the comb action of the irregular surfaces. 
     
     
       2. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 1 , wherein the screw processed to form an irregular surface for controlling the degree of combing and/or fiber length of the reinforcing fibers is an elliptical cylindrical or columnar screw whose surface is roughened. 
     
     
       3. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 1 , wherein the irregular surface roughness is oriented perpendicular to the screw axis. 
     
     
       4. A process for production of a fiber reinforced thermoplastic resin structure by melt extrusion by an extruder of a thermoplastic resin and a continuous roving, said process for production of a fiber reinforced thermoplastic rein structure characterized by passing a molten thermoplastic resin and reinforcing fibers through a control mechanism formed by processing a screw and/or cylinder to give at least part of the screw surface and/or the cylinder inner wall irregular surfaces and thereby controlling the degree of combing and/or fiber length of the reinforcing fibers in the thermoplastic resin matrix of the comb action of the irregular surfaces, wherein the irregular surfaces are roughened and front tips of projecting portions are shaped as blade edges. 
     
     
       5. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 4 , wherein blade angle is not more than 60°. 
     
     
       6. A process for production of a fiber reinforced thermoplastic resin structure by melt extrusion by an extruder of a thermoplastic resin and a continuous roving, said process for production of a fiber reinforced thermoplastic rein structure characterized by passing a molten thermoplastic resin and reinforcing fibers through a control mechanism formed by processing a screw and/or cylinder to give at least part of the screw surface and/or the cylinder inner wall irregular surfaces and thereby controlling the degree of combing and/or fiber length of the reinforcing fibers in the thermoplastic resin matrix of the comb action of the irregular surfaces, wherein use is made of an extruder provided with one or more plates aligned parallel to the screw axis and inside the cylinder between the front end of the extruder screw and die so as to correct the spiral flow of the mixed melt controlled in the degree of combing and/or fiber length of the reinforcing fibers. 
     
     
       7. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 6 , comprising using an extruder provided with plates with at least a partially wedge shaped cross-section. 
     
     
       8. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 6 , comprising using an extruder having curved plates. 
     
     
       9. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 6 , comprising using an extruder having a plurality of plates mounted in a lattice form. 
     
     
       10. A process for production of a fiber reinforced thermoplastic resin structure by melt extrusion by an extruder of a thermoplastic resin and a continuous roving, said process for production of a fiber reinforced thermoplastic rein structure characterized by passing a molten thermoplastic resin and reinforcing fibers through a control mechanism formed by processing a screw and/or cylinder to give at least part of the screw surface and/or the cylinder inner wall irregular surfaces and thereby controlling the degree of combing and/or fiber length of the reinforcing fibers in the thermoplastic resin matrix of the comb action of the irregular surfaces, wherein 
       (1) said structure is a rod or pellet in shape and  
       (2) when producing the structure, the following die is used:  
       (i) said die is attached to the front end of the extruder directly or through an adaptor; and  
       (ii) said die is composed of a plate having a predetermined thickness in which a plurality of through holes are formed,  
       (a) at least a part of said through holes being frustoconical in shape  
       (b) the value of R/r being greater than 1 when the radii of the circles formed by the through holes at the extruder side and discharge side are R and r, respectively, and  
       (c) the total sectional area of the holes formed by the through holes at the extruder side being 90% of the sectional area of the extruder or the adaptor on the discharge side.  
     
     
       11. A process for the production of a fiber reinforces thermoplastic resin structure as claimed in  claim 10 , comprising using a die having parallel land portions of a fixed diameter in front of the through holes on the discharge side of the die. 
     
     
       12. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 10 , comprising using a die wherein d is the distance between centers of circles formed on the extruder side of a die by two adjoining through holes is not less than 10 mm. 
     
     
       13. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 10 , comprising using a die wherein the cones formed by at least part of adjoining through holes partially overlap and the overlapping portions are left empty or the overlapping portions are provided with wedge shaped partition plates. 
     
     
       14. A process for the production of a fiber reinforced thermoplastic resin structure as claimed in  claim 10 , comprising using a die wherein at least part of the through holes on the extruder side are enlarged so that the shape of the front end of the extruder to which the die is attached match or the cross-section of the adaptor on the discharge side and the shape of the holes formed by the through holes on the extruder side of the die match.